High dose rate (HDR) brachytherapy is a form of cancer therapy that utilizes high doses of ionizing radiation delivered over a short period of time (on the order of minutes) directly at or near a target.
In HDR brachytherapy of the prostate, hollow catheters are inserted via a template through the perineum of a patient and into the prostate of a patient, so that a segment of each catheter lies within the prostate of the patient. Care must be taken not to unnecessarily penetrate the bladder of the patient. Also, ensuring that the catheters are close to the boundaries of the prostate is an important clinical objective to reduce or minimize radiation dose to a central region of the prostate through which the urethra runs so as to reduce the likelihood of damage caused by the radiation to the urethra.
In a typical clinical workflow, the prostate boundaries are estimated subjectively and manually delineated by the clinician from pre-insertion transrectal ultrasound (TRUS) images. Therefore, the accuracy of inserting catheters close to the periphery of the prostate is highly dependent on the ability of the clinician to correctly and repeatedly identify the boundaries of the prostate (during catheter insertion), which are not always readily visible on TRUS images being provided to the clinician.
Sub-optimal catheter insertion can result in bladder punctures, uneven catheter distribution about the prostate, and catheters that are too close to the urethra the latter of which may adversely affect the dose coverage and/or increase radiation to normal tissue and/or structures in the vicinity of the prostate (e.g., the rectum) and is therefore undesirable.